scripts/recordmcount.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * recordmcount.c: construct a table of the locations of calls to 'mcount'
   4  * so that ftrace can find them quickly.
   5  * Copyright 2009 John F. Reiser <jreiser@BitWagon.com>.  All rights reserved.
   6  *
   7  * Restructured to fit Linux format, as well as other updates:
   8  *  Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc.
   9  */
  10
  11 /*
  12  * Strategy: alter the .o file in-place.
  13  *
  14  * Append a new STRTAB that has the new section names, followed by a new array
  15  * ElfXX_Shdr[] that has the new section headers, followed by the section
  16  * contents for __mcount_loc and its relocations.  The old shstrtab strings,
  17  * and the old ElfXX_Shdr[] array, remain as "garbage" (commonly, a couple
  18  * kilobytes.)  Subsequent processing by /bin/ld (or the kernel module loader)
  19  * will ignore the garbage regions, because they are not designated by the
  20  * new .e_shoff nor the new ElfXX_Shdr[].  [In order to remove the garbage,
  21  * then use "ld -r" to create a new file that omits the garbage.]
  22  */
  23
  24 #include <sys/types.h>
  25 #include <sys/mman.h>
  26 #include <sys/stat.h>
  27 #include <getopt.h>
  28 #include <elf.h>
  29 #include <fcntl.h>
  30 #include <stdio.h>
  31 #include <stdlib.h>
  32 #include <string.h>
  33 #include <unistd.h>
  34
  35 #ifndef EM_AARCH64
  36 #define EM_AARCH64      183
  37 #define R_AARCH64_NONE          0
  38 #define R_AARCH64_ABS64 257
  39 #endif
  40
  41 #ifndef EM_LOONGARCH
  42 #define EM_LOONGARCH            258
  43 #define R_LARCH_32                      1
  44 #define R_LARCH_64                      2
  45 #define R_LARCH_MARK_LA                 20
  46 #define R_LARCH_SOP_PUSH_PLT_PCREL      29
  47 #endif
  48
  49 #define R_ARM_PC24              1
  50 #define R_ARM_THM_CALL          10
  51 #define R_ARM_CALL              28
  52
  53 #define R_AARCH64_CALL26        283
  54
  55 static int fd_map;      /* File descriptor for file being modified. */
  56 static int mmap_failed; /* Boolean flag. */
  57 static char gpfx;       /* prefix for global symbol name (sometimes '_') */
  58 static struct stat sb;  /* Remember .st_size, etc. */
  59 static const char *altmcount;   /* alternate mcount symbol name */
  60 static int warn_on_notrace_sect; /* warn when section has mcount not being recorded */
  61 static void *file_map;  /* pointer of the mapped file */
  62 static void *file_end;  /* pointer to the end of the mapped file */
  63 static int file_updated; /* flag to state file was changed */
  64 static void *file_ptr;  /* current file pointer location */
  65
  66 static void *file_append; /* added to the end of the file */
  67 static size_t file_append_size; /* how much is added to end of file */
  68
  69 /* Per-file resource cleanup when multiple files. */
  70 static void file_append_cleanup(void)
  71 {
  72         free(file_append);
  73         file_append = NULL;
  74         file_append_size = 0;
  75         file_updated = 0;
  76 }
  77
  78 static void mmap_cleanup(void)
  79 {
  80         if (!mmap_failed)
  81                 munmap(file_map, sb.st_size);
  82         else
  83                 free(file_map);
  84         file_map = NULL;
  85 }
  86
  87 /* ulseek, uwrite, ...:  Check return value for errors. */
  88
  89 static off_t ulseek(off_t const offset, int const whence)
  90 {
  91         switch (whence) {
  92         case SEEK_SET:
  93                 file_ptr = file_map + offset;
  94                 break;
  95         case SEEK_CUR:
  96                 file_ptr += offset;
  97                 break;
  98         case SEEK_END:
  99                 file_ptr = file_map + (sb.st_size - offset);
 100                 break;
 101         }
 102         if (file_ptr < file_map) {
 103                 fprintf(stderr, "lseek: seek before file\n");
 104                 return -1;
 105         }
 106         return file_ptr - file_map;
 107 }
 108
 109 static ssize_t uwrite(void const *const buf, size_t const count)
 110 {
 111         size_t cnt = count;
 112         off_t idx = 0;
 113
 114         file_updated = 1;
 115
 116         if (file_ptr + count >= file_end) {
 117                 off_t aoffset = (file_ptr + count) - file_end;
 118
 119                 if (aoffset > file_append_size) {
 120                         file_append = realloc(file_append, aoffset);
 121                         file_append_size = aoffset;
 122                 }
 123                 if (!file_append) {
 124                         perror("write");
 125                         file_append_cleanup();
 126                         mmap_cleanup();
 127                         return -1;
 128                 }
 129                 if (file_ptr < file_end) {
 130                         cnt = file_end - file_ptr;
 131                 } else {
 132                         cnt = 0;
 133                         idx = aoffset - count;
 134                 }
 135         }
 136
 137         if (cnt)
 138                 memcpy(file_ptr, buf, cnt);
 139
 140         if (cnt < count)
 141                 memcpy(file_append + idx, buf + cnt, count - cnt);
 142
 143         file_ptr += count;
 144         return count;
 145 }
 146
 147 static void * umalloc(size_t size)
 148 {
 149         void *const addr = malloc(size);
 150         if (addr == 0) {
 151                 fprintf(stderr, "malloc failed: %zu bytes\n", size);
 152                 file_append_cleanup();
 153                 mmap_cleanup();
 154                 return NULL;
 155         }
 156         return addr;
 157 }
 158
 159 /*
 160  * Get the whole file as a programming convenience in order to avoid
 161  * malloc+lseek+read+free of many pieces.  If successful, then mmap
 162  * avoids copying unused pieces; else just read the whole file.
 163  * Open for both read and write; new info will be appended to the file.
 164  * Use MAP_PRIVATE so that a few changes to the in-memory ElfXX_Ehdr
 165  * do not propagate to the file until an explicit overwrite at the last.
 166  * This preserves most aspects of consistency (all except .st_size)
 167  * for simultaneous readers of the file while we are appending to it.
 168  * However, multiple writers still are bad.  We choose not to use
 169  * locking because it is expensive and the use case of kernel build
 170  * makes multiple writers unlikely.
 171  */
 172 static void *mmap_file(char const *fname)
 173 {
 174         /* Avoid problems if early cleanup() */
 175         fd_map = -1;
 176         mmap_failed = 1;
 177         file_map = NULL;
 178         file_ptr = NULL;
 179         file_updated = 0;
 180         sb.st_size = 0;
 181
 182         fd_map = open(fname, O_RDONLY);
 183         if (fd_map < 0) {
 184                 perror(fname);
 185                 return NULL;
 186         }
 187         if (fstat(fd_map, &sb) < 0) {
 188                 perror(fname);
 189                 goto out;
 190         }
 191         if (!S_ISREG(sb.st_mode)) {
 192                 fprintf(stderr, "not a regular file: %s\n", fname);
 193                 goto out;
 194         }
 195         file_map = mmap(0, sb.st_size, PROT_READ|PROT_WRITE, MAP_PRIVATE,
 196                         fd_map, 0);
 197         if (file_map == MAP_FAILED) {
 198                 mmap_failed = 1;
 199                 file_map = umalloc(sb.st_size);
 200                 if (!file_map) {
 201                         perror(fname);
 202                         goto out;
 203                 }
 204                 if (read(fd_map, file_map, sb.st_size) != sb.st_size) {
 205                         perror(fname);
 206                         free(file_map);
 207                         file_map = NULL;
 208                         goto out;
 209                 }
 210         } else
 211                 mmap_failed = 0;
 212 out:
 213         close(fd_map);
 214         fd_map = -1;
 215
 216         file_end = file_map + sb.st_size;
 217
 218         return file_map;
 219 }
 220
 221
 222 static unsigned char ideal_nop5_x86_64[5] = { 0x0f, 0x1f, 0x44, 0x00, 0x00 };
 223 static unsigned char ideal_nop5_x86_32[5] = { 0x3e, 0x8d, 0x74, 0x26, 0x00 };
 224 static unsigned char *ideal_nop;
 225
 226 static char rel_type_nop;
 227
 228 static int (*make_nop)(void *map, size_t const offset);
 229
 230 static int make_nop_x86(void *map, size_t const offset)
 231 {
 232         uint32_t *ptr;
 233         unsigned char *op;
 234
 235         /* Confirm we have 0xe8 0x0 0x0 0x0 0x0 */
 236         ptr = map + offset;
 237         if (*ptr != 0)
 238                 return -1;
 239
 240         op = map + offset - 1;
 241         if (*op != 0xe8)
 242                 return -1;
 243
 244         /* convert to nop */
 245         if (ulseek(offset - 1, SEEK_SET) < 0)
 246                 return -1;
 247         if (uwrite(ideal_nop, 5) < 0)
 248                 return -1;
 249         return 0;
 250 }
 251
 252 static unsigned char ideal_nop4_arm_le[4] = { 0x00, 0x00, 0xa0, 0xe1 }; /* mov r0, r0 */
 253 static unsigned char ideal_nop4_arm_be[4] = { 0xe1, 0xa0, 0x00, 0x00 }; /* mov r0, r0 */
 254 static unsigned char *ideal_nop4_arm;
 255
 256 static unsigned char bl_mcount_arm_le[4] = { 0xfe, 0xff, 0xff, 0xeb }; /* bl */
 257 static unsigned char bl_mcount_arm_be[4] = { 0xeb, 0xff, 0xff, 0xfe }; /* bl */
 258 static unsigned char *bl_mcount_arm;
 259
 260 static unsigned char push_arm_le[4] = { 0x04, 0xe0, 0x2d, 0xe5 }; /* push {lr} */
 261 static unsigned char push_arm_be[4] = { 0xe5, 0x2d, 0xe0, 0x04 }; /* push {lr} */
 262 static unsigned char *push_arm;
 263
 264 static unsigned char ideal_nop2_thumb_le[2] = { 0x00, 0xbf }; /* nop */
 265 static unsigned char ideal_nop2_thumb_be[2] = { 0xbf, 0x00 }; /* nop */
 266 static unsigned char *ideal_nop2_thumb;
 267
 268 static unsigned char push_bl_mcount_thumb_le[6] = { 0x00, 0xb5, 0xff, 0xf7, 0xfe, 0xff }; /* push {lr}, bl */
 269 static unsigned char push_bl_mcount_thumb_be[6] = { 0xb5, 0x00, 0xf7, 0xff, 0xff, 0xfe }; /* push {lr}, bl */
 270 static unsigned char *push_bl_mcount_thumb;
 271
 272 static int make_nop_arm(void *map, size_t const offset)
 273 {
 274         char *ptr;
 275         int cnt = 1;
 276         int nop_size;
 277         size_t off = offset;
 278
 279         ptr = map + offset;
 280         if (memcmp(ptr, bl_mcount_arm, 4) == 0) {
 281                 if (memcmp(ptr - 4, push_arm, 4) == 0) {
 282                         off -= 4;
 283                         cnt = 2;
 284                 }
 285                 ideal_nop = ideal_nop4_arm;
 286                 nop_size = 4;
 287         } else if (memcmp(ptr - 2, push_bl_mcount_thumb, 6) == 0) {
 288                 cnt = 3;
 289                 nop_size = 2;
 290                 off -= 2;
 291                 ideal_nop = ideal_nop2_thumb;
 292         } else
 293                 return -1;
 294
 295         /* Convert to nop */
 296         if (ulseek(off, SEEK_SET) < 0)
 297                 return -1;
 298
 299         do {
 300                 if (uwrite(ideal_nop, nop_size) < 0)
 301                         return -1;
 302         } while (--cnt > 0);
 303
 304         return 0;
 305 }
 306
 307 static unsigned char ideal_nop4_arm64[4] = {0x1f, 0x20, 0x03, 0xd5};
 308 static int make_nop_arm64(void *map, size_t const offset)
 309 {
 310         uint32_t *ptr;
 311
 312         ptr = map + offset;
 313         /* bl <_mcount> is 0x94000000 before relocation */
 314         if (*ptr != 0x94000000)
 315                 return -1;
 316
 317         /* Convert to nop */
 318         if (ulseek(offset, SEEK_SET) < 0)
 319                 return -1;
 320         if (uwrite(ideal_nop, 4) < 0)
 321                 return -1;
 322         return 0;
 323 }
 324
 325 static int write_file(const char *fname)
 326 {
 327         char tmp_file[strlen(fname) + 4];
 328         size_t n;
 329
 330         if (!file_updated)
 331                 return 0;
 332
 333         sprintf(tmp_file, "%s.rc", fname);
 334
 335         /*
 336          * After reading the entire file into memory, delete it
 337          * and write it back, to prevent weird side effects of modifying
 338          * an object file in place.
 339          */
 340         fd_map = open(tmp_file, O_WRONLY | O_TRUNC | O_CREAT, sb.st_mode);
 341         if (fd_map < 0) {
 342                 perror(fname);
 343                 return -1;
 344         }
 345         n = write(fd_map, file_map, sb.st_size);
 346         if (n != sb.st_size) {
 347                 perror("write");
 348                 close(fd_map);
 349                 return -1;
 350         }
 351         if (file_append_size) {
 352                 n = write(fd_map, file_append, file_append_size);
 353                 if (n != file_append_size) {
 354                         perror("write");
 355                         close(fd_map);
 356                         return -1;
 357                 }
 358         }
 359         close(fd_map);
 360         if (rename(tmp_file, fname) < 0) {
 361                 perror(fname);
 362                 return -1;
 363         }
 364         return 0;
 365 }
 366
 367 /* w8rev, w8nat, ...: Handle endianness. */
 368
 369 static uint64_t w8rev(uint64_t const x)
 370 {
 371         return   ((0xff & (x >> (0 * 8))) << (7 * 8))
 372                | ((0xff & (x >> (1 * 8))) << (6 * 8))
 373                | ((0xff & (x >> (2 * 8))) << (5 * 8))
 374                | ((0xff & (x >> (3 * 8))) << (4 * 8))
 375                | ((0xff & (x >> (4 * 8))) << (3 * 8))
 376                | ((0xff & (x >> (5 * 8))) << (2 * 8))
 377                | ((0xff & (x >> (6 * 8))) << (1 * 8))
 378                | ((0xff & (x >> (7 * 8))) << (0 * 8));
 379 }
 380
 381 static uint32_t w4rev(uint32_t const x)
 382 {
 383         return   ((0xff & (x >> (0 * 8))) << (3 * 8))
 384                | ((0xff & (x >> (1 * 8))) << (2 * 8))
 385                | ((0xff & (x >> (2 * 8))) << (1 * 8))
 386                | ((0xff & (x >> (3 * 8))) << (0 * 8));
 387 }
 388
 389 static uint32_t w2rev(uint16_t const x)
 390 {
 391         return   ((0xff & (x >> (0 * 8))) << (1 * 8))
 392                | ((0xff & (x >> (1 * 8))) << (0 * 8));
 393 }
 394
 395 static uint64_t w8nat(uint64_t const x)
 396 {
 397         return x;
 398 }
 399
 400 static uint32_t w4nat(uint32_t const x)
 401 {
 402         return x;
 403 }
 404
 405 static uint32_t w2nat(uint16_t const x)
 406 {
 407         return x;
 408 }
 409
 410 static uint64_t (*w8)(uint64_t);
 411 static uint32_t (*w)(uint32_t);
 412 static uint32_t (*w2)(uint16_t);
 413
 414 /* Names of the sections that could contain calls to mcount. */
 415 static int is_mcounted_section_name(char const *const txtname)
 416 {
 417         return strncmp(".text",          txtname, 5) == 0 ||
 418                 strcmp(".init.text",     txtname) == 0 ||
 419                 strcmp(".ref.text",      txtname) == 0 ||
 420                 strcmp(".sched.text",    txtname) == 0 ||
 421                 strcmp(".spinlock.text", txtname) == 0 ||
 422                 strcmp(".irqentry.text", txtname) == 0 ||
 423                 strcmp(".softirqentry.text", txtname) == 0 ||
 424                 strcmp(".kprobes.text", txtname) == 0 ||
 425                 strcmp(".cpuidle.text", txtname) == 0;
 426 }
 427
 428 static char const *already_has_rel_mcount = "success"; /* our work here is done! */
 429
 430 /* 32 bit and 64 bit are very similar */
 431 #include "recordmcount.h"
 432 #define RECORD_MCOUNT_64
 433 #include "recordmcount.h"
 434
 435 static int arm_is_fake_mcount(Elf32_Rel const *rp)
 436 {
 437         switch (ELF32_R_TYPE(w(rp->r_info))) {
 438         case R_ARM_THM_CALL:
 439         case R_ARM_CALL:
 440         case R_ARM_PC24:
 441                 return 0;
 442         }
 443
 444         return 1;
 445 }
 446
 447 static int arm64_is_fake_mcount(Elf64_Rel const *rp)
 448 {
 449         return ELF64_R_TYPE(w8(rp->r_info)) != R_AARCH64_CALL26;
 450 }
 451
 452 static int LARCH32_is_fake_mcount(Elf32_Rel const *rp)
 453 {
 454         switch (ELF64_R_TYPE(w(rp->r_info))) {
 455         case R_LARCH_MARK_LA:
 456         case R_LARCH_SOP_PUSH_PLT_PCREL:
 457                 return 0;
 458         }
 459
 460         return 1;
 461 }
 462
 463 static int LARCH64_is_fake_mcount(Elf64_Rel const *rp)
 464 {
 465         switch (ELF64_R_TYPE(w(rp->r_info))) {
 466         case R_LARCH_MARK_LA:
 467         case R_LARCH_SOP_PUSH_PLT_PCREL:
 468                 return 0;
 469         }
 470
 471         return 1;
 472 }
 473
 474 /* 64-bit EM_MIPS has weird ELF64_Rela.r_info.
 475  * http://techpubs.sgi.com/library/manuals/4000/007-4658-001/pdf/007-4658-001.pdf
 476  * We interpret Table 29 Relocation Operation (Elf64_Rel, Elf64_Rela) [p.40]
 477  * to imply the order of the members; the spec does not say so.
 478  *      typedef unsigned char Elf64_Byte;
 479  * fails on MIPS64 because their <elf.h> already has it!
 480  */
 481
 482 typedef uint8_t myElf64_Byte;           /* Type for a 8-bit quantity.  */
 483
 484 union mips_r_info {
 485         Elf64_Xword r_info;
 486         struct {
 487                 Elf64_Word r_sym;               /* Symbol index.  */
 488                 myElf64_Byte r_ssym;            /* Special symbol.  */
 489                 myElf64_Byte r_type3;           /* Third relocation.  */
 490                 myElf64_Byte r_type2;           /* Second relocation.  */
 491                 myElf64_Byte r_type;            /* First relocation.  */
 492         } r_mips;
 493 };
 494
 495 static uint64_t MIPS64_r_sym(Elf64_Rel const *rp)
 496 {
 497         return w(((union mips_r_info){ .r_info = rp->r_info }).r_mips.r_sym);
 498 }
 499
 500 static void MIPS64_r_info(Elf64_Rel *const rp, unsigned sym, unsigned type)
 501 {
 502         rp->r_info = ((union mips_r_info){
 503                 .r_mips = { .r_sym = w(sym), .r_type = type }
 504         }).r_info;
 505 }
 506
 507 static int do_file(char const *const fname)
 508 {
 509         unsigned int reltype = 0;
 510         Elf32_Ehdr *ehdr;
 511         int rc = -1;
 512
 513         ehdr = mmap_file(fname);
 514         if (!ehdr)
 515                 goto out;
 516
 517         w = w4nat;
 518         w2 = w2nat;
 519         w8 = w8nat;
 520         switch (ehdr->e_ident[EI_DATA]) {
 521                 static unsigned int const endian = 1;
 522         default:
 523                 fprintf(stderr, "unrecognized ELF data encoding %d: %s\n",
 524                         ehdr->e_ident[EI_DATA], fname);
 525                 goto out;
 526         case ELFDATA2LSB:
 527                 if (*(unsigned char const *)&endian != 1) {
 528                         /* main() is big endian, file.o is little endian. */
 529                         w = w4rev;
 530                         w2 = w2rev;
 531                         w8 = w8rev;
 532                 }
 533                 ideal_nop4_arm = ideal_nop4_arm_le;
 534                 bl_mcount_arm = bl_mcount_arm_le;
 535                 push_arm = push_arm_le;
 536                 ideal_nop2_thumb = ideal_nop2_thumb_le;
 537                 push_bl_mcount_thumb = push_bl_mcount_thumb_le;
 538                 break;
 539         case ELFDATA2MSB:
 540                 if (*(unsigned char const *)&endian != 0) {
 541                         /* main() is little endian, file.o is big endian. */
 542                         w = w4rev;
 543                         w2 = w2rev;
 544                         w8 = w8rev;
 545                 }
 546                 ideal_nop4_arm = ideal_nop4_arm_be;
 547                 bl_mcount_arm = bl_mcount_arm_be;
 548                 push_arm = push_arm_be;
 549                 ideal_nop2_thumb = ideal_nop2_thumb_be;
 550                 push_bl_mcount_thumb = push_bl_mcount_thumb_be;
 551                 break;
 552         }  /* end switch */
 553         if (memcmp(ELFMAG, ehdr->e_ident, SELFMAG) != 0 ||
 554             w2(ehdr->e_type) != ET_REL ||
 555             ehdr->e_ident[EI_VERSION] != EV_CURRENT) {
 556                 fprintf(stderr, "unrecognized ET_REL file %s\n", fname);
 557                 goto out;
 558         }
 559
 560         gpfx = '_';
 561         switch (w2(ehdr->e_machine)) {
 562         default:
 563                 fprintf(stderr, "unrecognized e_machine %u %s\n",
 564                         w2(ehdr->e_machine), fname);
 565                 goto out;
 566         case EM_386:
 567                 reltype = R_386_32;
 568                 rel_type_nop = R_386_NONE;
 569                 make_nop = make_nop_x86;
 570                 ideal_nop = ideal_nop5_x86_32;
 571                 mcount_adjust_32 = -1;
 572                 gpfx = 0;
 573                 break;
 574         case EM_ARM:
 575                 reltype = R_ARM_ABS32;
 576                 altmcount = "__gnu_mcount_nc";
 577                 make_nop = make_nop_arm;
 578                 rel_type_nop = R_ARM_NONE;
 579                 is_fake_mcount32 = arm_is_fake_mcount;
 580                 gpfx = 0;
 581                 break;
 582         case EM_AARCH64:
 583                 reltype = R_AARCH64_ABS64;
 584                 make_nop = make_nop_arm64;
 585                 rel_type_nop = R_AARCH64_NONE;
 586                 ideal_nop = ideal_nop4_arm64;
 587                 is_fake_mcount64 = arm64_is_fake_mcount;
 588                 break;
 589         case EM_IA_64:  reltype = R_IA64_IMM64; break;
 590         case EM_MIPS:   /* reltype: e_class    */ break;
 591         case EM_LOONGARCH:      /* reltype: e_class    */ break;
 592         case EM_PPC:    reltype = R_PPC_ADDR32; break;
 593         case EM_PPC64:  reltype = R_PPC64_ADDR64; break;
 594         case EM_S390:   /* reltype: e_class    */ break;
 595         case EM_SH:     reltype = R_SH_DIR32; gpfx = 0; break;
 596         case EM_SPARCV9: reltype = R_SPARC_64; break;
 597         case EM_X86_64:
 598                 make_nop = make_nop_x86;
 599                 ideal_nop = ideal_nop5_x86_64;
 600                 reltype = R_X86_64_64;
 601                 rel_type_nop = R_X86_64_NONE;
 602                 mcount_adjust_64 = -1;
 603                 gpfx = 0;
 604                 break;
 605         }  /* end switch */
 606
 607         switch (ehdr->e_ident[EI_CLASS]) {
 608         default:
 609                 fprintf(stderr, "unrecognized ELF class %d %s\n",
 610                         ehdr->e_ident[EI_CLASS], fname);
 611                 goto out;
 612         case ELFCLASS32:
 613                 if (w2(ehdr->e_ehsize) != sizeof(Elf32_Ehdr)
 614                 ||  w2(ehdr->e_shentsize) != sizeof(Elf32_Shdr)) {
 615                         fprintf(stderr,
 616                                 "unrecognized ET_REL file: %s\n", fname);
 617                         goto out;
 618                 }
 619                 if (w2(ehdr->e_machine) == EM_MIPS) {
 620                         reltype = R_MIPS_32;
 621                         is_fake_mcount32 = MIPS32_is_fake_mcount;
 622                 }
 623                 if (w2(ehdr->e_machine) == EM_LOONGARCH) {
 624                         reltype = R_LARCH_32;
 625                         is_fake_mcount32 = LARCH32_is_fake_mcount;
 626                 }
 627                 if (do32(ehdr, fname, reltype) < 0)
 628                         goto out;
 629                 break;
 630         case ELFCLASS64: {
 631                 Elf64_Ehdr *const ghdr = (Elf64_Ehdr *)ehdr;
 632                 if (w2(ghdr->e_ehsize) != sizeof(Elf64_Ehdr)
 633                 ||  w2(ghdr->e_shentsize) != sizeof(Elf64_Shdr)) {
 634                         fprintf(stderr,
 635                                 "unrecognized ET_REL file: %s\n", fname);
 636                         goto out;
 637                 }
 638                 if (w2(ghdr->e_machine) == EM_S390) {
 639                         reltype = R_390_64;
 640                         mcount_adjust_64 = -14;
 641                 }
 642                 if (w2(ghdr->e_machine) == EM_MIPS) {
 643                         reltype = R_MIPS_64;
 644                         Elf64_r_sym = MIPS64_r_sym;
 645                         Elf64_r_info = MIPS64_r_info;
 646                         is_fake_mcount64 = MIPS64_is_fake_mcount;
 647                 }
 648                 if (w2(ghdr->e_machine) == EM_LOONGARCH) {
 649                         reltype = R_LARCH_64;
 650                         is_fake_mcount64 = LARCH64_is_fake_mcount;
 651                 }
 652                 if (do64(ghdr, fname, reltype) < 0)
 653                         goto out;
 654                 break;
 655         }
 656         }  /* end switch */
 657
 658         rc = write_file(fname);
 659 out:
 660         file_append_cleanup();
 661         mmap_cleanup();
 662         return rc;
 663 }
 664
 665 int main(int argc, char *argv[])
 666 {
 667         const char ftrace[] = "/ftrace.o";
 668         int ftrace_size = sizeof(ftrace) - 1;
 669         int n_error = 0;  /* gcc-4.3.0 false positive complaint */
 670         int c;
 671         int i;
 672
 673         while ((c = getopt(argc, argv, "w")) >= 0) {
 674                 switch (c) {
 675                 case 'w':
 676                         warn_on_notrace_sect = 1;
 677                         break;
 678                 default:
 679                         fprintf(stderr, "usage: recordmcount [-w] file.o...\n");
 680                         return 0;
 681                 }
 682         }
 683
 684         if ((argc - optind) < 1) {
 685                 fprintf(stderr, "usage: recordmcount [-w] file.o...\n");
 686                 return 0;
 687         }
 688
 689         /* Process each file in turn, allowing deep failure. */
 690         for (i = optind; i < argc; i++) {
 691                 char *file = argv[i];
 692                 int len;
 693
 694                 /*
 695                  * The file kernel/trace/ftrace.o references the mcount
 696                  * function but does not call it. Since ftrace.o should
 697                  * not be traced anyway, we just skip it.
 698                  */
 699                 len = strlen(file);
 700                 if (len >= ftrace_size &&
 701                     strcmp(file + (len - ftrace_size), ftrace) == 0)
 702                         continue;
 703
 704                 if (do_file(file)) {
 705                         fprintf(stderr, "%s: failed\n", file);
 706                         ++n_error;
 707                 }
 708         }
 709         return !!n_error;
 710 }